Solution having a low freezing-point.



L. JL U FIPBBOB GEORGE FERGUSON, OF NEW.YORK, N. Y., ASSIGNOR TO PYRENE MANUFACTURWG COMPANY, A CORPORATION OF DELAWARE.

SOLUTION HAVING A LOW FREEZING-POINT.

No Drawing.

To all whom it may concern:

Be it known that I, GEORGE E. FERGUSON, a citizen of the United States, and resident of the city, county, and State of New York, have invented certain new and useful Improvements in Solutions Having a Low Freezing-Point, of which the following is a specification.

The object of this invention is to produce a compound having a low freezing point or,

' more specifically, to lower the normal freezing point of the basic element of the compound. Carbon tetra chlorid has been selected as illustrative of a basic element, which, being a solvent for many othercompounds, is useful for many purposes, among which fire extinguishing compounds may be mentioned, carbon tetra chlorid being inflammable.

The extensive uses to which carbon tetra chlorid is put, make it desirable to lower its normal freezing point (which in the chemically pure state is 19.'5-G;) to p'ermitits use in temperatures where extreme cold weather prevails; that it may be utilized as a liquid and at the same time maintain all of its useful properties.

With this in mind, I have performed a large number of experiments to ascertain if some underlying principle can be made to govern this depression of the freezing oint.

It is a well known fact that, consi ering inorganic compounds and the inorganic solvents, that the depression of the freezing point depends upon the solubility of the salts used and the degree of dissociation which takes place when these salts are dissolved in the solvent (which solvent, in most cases, is water),

The laws governin the depression of the freezing point for e ectrolytes are simple:

-1. The freezing point of a solution is lower than that of the pure solvent.

2. The depression of the freezing point is proportional to the concentration of the solution.

3. If t degrees be the depression produced by the presence of p gramsof substance in 100 grams of the solvent, then the molecular depression (where m is the molecular weight of the dissolved substance).

Specification of Letters Patent.

Patented Oct. 16, 1917.

These laws do not hold good in the depression of the freezing point of carbon tetra chlorid. A good example of this is in the solution of a compound like azo benzene (C H N C H which is very soluble in carbon tetra chlorid. When this substance is added the result is a higher freezing point than that of the carbon tetra chlorid alone,

It was found that among the great variety of compounds tried out about 150 accomplished the desired result.

It is understood that some of these compounds would prove detrimental to the use of, carbon tetra chlorid under certain oonditions while they might prove very acceptable under others.

To simplify the list, it was thought best to classify these substances under different chemical groups, such as, (1) esters and 'ethers; (2) amine and amino compounds;

.(3) aldehydes and ketones; (4) alcohols;

(5) oils; (6) hydrocarbons, substitutes and derivatives; (7) phenols and phenol derivatives;' (8) terpenes, camphors and (9) acids, etc.

About the only generality which can be made in regardto all this investigation is the fact that most compounds which are in the liquid state at 'normal (room) tembon tetra chlorid, lower the freezing point of the carbon tetra chlorid, and vice versa, most of the compounds which are solid at normal tem erature and soluble in carbon tetra chlori do not lower the freezing point but in most cases raise it. There are, however, enough exceptions to this generality to render it impossible of general application as a rule.

In this investigation no attempt was made to determine the quantity of substance dissolved in a known amount of solvent to produce an observed depression of the freezing point. It was thought that sufiicient knowledge was gained in determining just what substances would accomplish the desired depressing effect on the freezing point.

'peratures and which are soluble in car- Considering the group of phenols and phenol derivatives the following may be taken as a definition:

A phenol is the hydroxy derivative of the aromatic hydrocarbons, for example: aromatic hydrocarbon benzene, 0 H phenol from benzene or carbolic acid, (which is improperly named and acid because of its corrosive action). Carbolic acid or phenol '(C H OH) is similar in structure to an alcohol of the aromatic series of hydrocarbons.

The following are examples of this group:

Benzonaphthol, OHC H COOC H creosote (white) no standard formula; carvacrol,

CH: 2: 1 creosote CgI0lfbg0H standardl foz'gmla; aiacol thymo H am n, 0H, b1i. 3 2 It .is obvious that it is impossible to cover every compound, in the manner described,

to ascertain if the freezing point of carbon tetra chlorid could be lowered by dissolving the compound therein. I have, however,

' made tests in each class of compounds with commercially possible examples in each 77 class. What future developments may be made toward the reduction of the cost of a number of the expensive compounds, thus rendering the same commercially possible is problematical but my experiments and tests show that it is possible to generalize in these different classes or divisions.

Four hundred and thirty experiments were performed, the substances selected being taken from the chemical catalogues. All of the organic substances costing one dollar or less were tried-as it was considered that these compounds from the standpoint of cost, would be commercially possible. It was found that a great many of these compounds were insoluble in carbon tetra chlorid and therefore eleminated themselves from the investigation.

What I claim is:

A solution having a low freezing point comprising carbon tetra chlorid and thymol in solution.

Signed at the city,- count and State of New York, this 8th day of ct., 1914.

' GEORGE E. FERGUSON.

Witnesses:

HAROLD W. CHAPMAN,

J. Doom'n'mn. 

